Along an assembly line, various types of articles, such as for example, diapers and other absorbent articles, may be assembled by adding components to and otherwise modifying an advancing, continuous web of material. For example, in some processes, advancing webs of material are combined with other advancing webs of material. In other examples, individual components created from advancing webs of material are combined with advancing webs of material, which in turn, are then combined with other advancing webs of material. Webs of material and component parts used to manufacture diapers may include: backsheets, topsheets, absorbent cores, front and/or back ears, fastener components, and various types of elastic webs and components such as leg elastics, barrier leg cuff elastics, and waist elastics. Once the desired component parts are assembled, the advancing web(s) and component parts are subjected to a final knife cut to separate the web(s) into discrete diapers or other absorbent articles. The discrete diapers or absorbent articles may also then be folded and packaged.
Various methods and apparatuses may be used for attaching different components to the advancing web and/or otherwise modify the advancing web. For example, some production operations are configured to apply relatively high viscosity fluids, such as hot melt adhesives, to elastic strands to be combined with an advancing web to create an elastic laminate. In some instances, the production operations are configured to apply hot melt adhesives to advancing elastic strands and/or a web in pre-determined patterns. These operations may include the use of systems and methods such as slot die coating, direct gravure, offset gravure and reverse gravure roll coating processes that are extensively described in the art. However, current systems and methods for applying adhesives to an advancing substrate and/or elastic strands may have certain limitations.
For example, some manufacturing processes of absorbent articles such as feminine hygiene pads, baby diapers, and adult incontinence pads use electro-pneumatic switching valves to intermittently transfer adhesive to advancing elastic strands and/or substrates. However, the quality and precision of intermittent transfer of fluids to advancing elastics and/or substrates may be limited by the speed of the on/off cycle of switching valves used to interrupt the flow of fluid to the adhesive applicator. Thus, as web processing speeds increase, the ability of current adhesive application methods to achieve fine resolution of on/off coat patterns in the direction of web travel decreases. Consequently, it would be beneficial to provide apparatuses and methods that apply adhesives and other fluids to a substrate in patterns with relatively high resolution and high speeds without being limited by the speed of on/off cycling of switching valves used to interrupt the flow of fluid to the slot die of the fluid applicator.